Abstract: The element distribution near the Fe₃Al/Q235 diffusion welding interface was calculated and measured by means of electron probe microanalysis.The results indicated that the calculated value of Al and Fe content near the interface was close to the measured value.Element diffusion coefficient in the interface transition zone is larger than that in the base materials Fe₃Al and Q235 steel under the same temperature,and the phase structure near the Fe₃Al/Q235 interface is favorable to element diffusion.The diffusion distance of elements near the Fe₃Al/Q235 interface increased with the increasing of the heating temperature and the holding time.The relation between the width of the interface transition zone and the holding time conformed to parabolic growth law.The width of the interface transition zone was not increased obviously when the holding time was longer than 60 min.